What do you mean by a pseudo-class?

A pseudo-class is a selector that only chooses components that meet certain criteria, such as being the first of their kind or having the mouse pointer over them. They frequently assist you in reducing the number of unnecessary classes in your markup and provide more flexible, maintainable code by acting as though you had applied a class to a particular area of your document

A specific state of an element is specified by a pseudo-class. It can be utilised, for instance, to: When a user moves the mouse over an element, it is styled. links that have been visited and those that have not. Style as a component when it is highlighted